White birch bark crude extract, extraction method and application thereof

Abstract

The present application provides a white birch bark crude extract, an extraction method and application thereof. The white birch bark crude extract provided by the present application has a strong adsorption effect on calcite, and is not easy to adsorb fluorite ore. The selective adsorption enlarges the floatable difference between the gangue mineral calcite and the fluorite ore, and can be used as a calcite inhibitor in the fluorite ore flotation process. The extraction method provided by the present application is simple, efficient and low in processing cost. A large amount of bark residues generated in the process of white birch forest processing can be used as raw materials. The white birch bark extract obtained is low in price, more economical than high-purity commercial products, and therefore has a good application prospect.

Description

Crude extracts from birch bark, extraction methods and their applications Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a crude extract of birch bark and its extraction method, and the application of the crude extract of birch bark as a calcite inhibitor. Background Technology

[0002] Fluorine plays an irreplaceable role in hydrofluoric acid, opalescent glass, high-octane fuel catalysis, and ceramic production. Fluorite (CaF2) is the main source of fluorine and is listed as a national strategic mineral resource. Calcite is the most common gangue mineral in fluorite deposits. It has been reported that the content of associated calcite varies in different types of fluorite deposits; in calcite-type fluorite deposits, the associated calcite content can reach as high as 50%, while in barite-type, single-type, and quartz-type deposits, the calcite content is lower. Industrially, froth flotation is commonly used to separate fluorite and calcite. However, the similar calcium active sites on the surfaces of fluorite and calcite make efficient flotation separation a challenge in mineral processing.

[0003] Currently, commonly used depressants in fluorite flotation are mainly divided into inorganic and organic depressants. Inorganic depressants mainly include modified water glass and sodium hexametaphosphate, while organic depressants include starch, sodium humate, and tannins. However, organic depressants are more expensive, have lower solubility, and poorer stability. Water glass remains the most widely used inorganic depressant in industry. However, water glass has poor selectivity, good dispersibility, and is used in large quantities, which can lead to the suppression of some fluorite, increasing the difficulty of subsequent tailings particle settling treatment. Summary of the Invention

[0004] Birch is an important forest resource in my country, widely distributed in Northeast my country, North China, Henan, Shaanxi, Ningxia, Gansu, Qinghai, Sichuan, Yunnan, and southeastern Tibet. During its harvesting and processing, a large amount of residue is generated, including bark, tree tops, and timber cut-offs, which are currently underutilized. Birch bark can be used to extract betulinic triterpenes, the main components of which are betulinol and betulinic acid. Their molecular formulas contain functional groups such as hydroxyl, carboxyl, and six-membered carbon rings. The inventors discovered their potential as inhibitors; however, pure betulinic triterpenes are expensive and difficult to extract. The extraction method provided by this invention can conveniently obtain crude extracts from birch bark. These crude extracts, used as gangue mineral inhibitors in fluorite flotation, can effectively separate fluorite from calcite.

[0005] One of the objectives of this invention is to provide a method for extracting crude birch bark extract, the method comprising: soaking birch bark in an extractant containing alcohol to obtain an extract solution, and then evaporating the solvent of the extract solution to dryness to obtain crude birch bark extract.

[0006] In some embodiments, the extraction method includes: crushing dried birch bark, soaking the crushed birch bark in an ethanol solution, filtering after soaking, and obtaining the extract solution.

[0007] Furthermore, the dried birch bark is broken into pieces below -2mm before the soaking process is carried out.

[0008] Furthermore, the birch bark is soaked in an ethanol solution with a concentration of 65%-95%, wherein the amount of ethanol solution added is such that the mass fraction of the birch bark is 2%-5%.

[0009] Furthermore, the soaking time is more than 120 hours, and the stirring is carried out at a speed of 800-1200 r / min during the soaking process.

[0010] Furthermore, the solvent in the extract solution is evaporated to dryness at a temperature of 40-65°C.

[0011] The second objective of this invention is to provide a crude extract of birch bark obtained by any of the extraction methods described above.

[0012] A third objective of this invention is to provide the application of the crude birch bark extract as a calcite inhibitor.

[0013] In some embodiments, the application includes: in the flotation process of fluorite ore, using the crude extract of birch bark to selectively adsorb calcite, thereby separating calcite from fluorite ore.

[0014] In some embodiments, the application includes: preparing a slurry from fluorite ore containing calcite, and then adding at least an inhibitor and a collector to the slurry for flotation, wherein the inhibitor includes the birch bark crude extract described in any of the above technical solutions.

[0015] In some embodiments, the application specifically includes: grinding and adjusting the fluorite ore containing calcite to obtain a slurry; adjusting the pH of the slurry to 7-9; and adding the inhibitor and collector to the slurry at the pH value for flotation.

[0016] In some embodiments, during the flotation process, the amount of crude birch bark extract used is 500-1800 g / t. This amount is calculated based on the dry weight of the crude birch bark extract.

[0017] In some embodiments, the amount of collector used in the flotation process is 800-1500 g / t.

[0018] In some embodiments, the collector may be any fluorite ore collector in the prior art, such as sodium oleate, lauric acid, oxidized paraffin soap, etc., but is not limited thereto.

[0019] In some embodiments, the application further includes: performing one or more fine cleaning processes on the fluorite rough obtained by flotation, with a collector added in each fine cleaning process to obtain fluorite concentrate.

[0020] Furthermore, in each selection process, the amount of collector used is 300-800g / t.

[0021] In some embodiments, the application further includes: performing one or more scavenging processes on the tailings obtained from flotation to obtain the final tailings.

[0022] In some embodiments, the minerals with a fineness of -74 micrometers (meaning a fineness of less than 74 micrometers) account for 60%-85% of the slurry.

[0023] In some embodiments, the concentration of solid minerals in the slurry is 40%-50%.

[0024] In some embodiments, the inhibitor is added to the slurry and stirred for more than 3 minutes before the collector is added.

[0025] In some embodiments, the crude birch bark extract is dissolved in a methanol solution to prepare an inhibitor solution with a mass fraction of 0.5%, which is then added to the mineral slurry.

[0026] The fourth objective of this invention is to provide a flotation method for fluorite ore, comprising: crushing calcite-type fluorite ore to prepare a slurry, and then adding at least an inhibitor and a collector to the slurry for flotation; wherein the inhibitor includes any of the above-mentioned birch bark crude extracts. The main gangue mineral of the calcite-type fluorite ore is calcite.

[0027] In some embodiments, the fluorite ore flotation method specifically includes: grinding and adjusting the calcite-containing fluorite ore to obtain a slurry; adjusting the pH of the slurry to 7-9; and sequentially adding the inhibitor and collector to the slurry at the pH value for flotation.

[0028] In some embodiments, during the flotation process, the amount of crude birch bark extract used is 500-1800 g / t. This amount is calculated based on the dry weight of the crude birch bark extract.

[0029] In some embodiments, the amount of collector used in the flotation process is 800-1500 g / t.

[0030] In some embodiments, the collector may be any fluorite ore collector in the prior art, such as sodium oleate, lauric acid, oxidized paraffin soap, etc., but is not limited thereto.

[0031] In some embodiments, the fluorite flotation method further includes: performing one or more fine cleaning processes on the fluorite rough obtained from flotation, with a collector added in each fine cleaning process to obtain fluorite concentrate.

[0032] Furthermore, in each selection process, the amount of collector used is 300-800g / t.

[0033] In some embodiments, the application further includes: performing one or more scavenging processes on the tailings obtained from flotation to obtain the final tailings.

[0034] In some embodiments, the minerals with a fineness of -74 micrometers (i.e., fineness below 74 micrometers) account for 60%-85% of the slurry.

[0035] In some embodiments, the concentration of solid minerals in the slurry is 40%-50%.

[0036] In some embodiments, the inhibitor is added to the slurry and stirred for more than 3 minutes before the collector is added.

[0037] In some embodiments, the crude birch bark extract is dissolved in a methanol solution to prepare an inhibitor solution with a mass fraction of 0.5%, which is then added to the mineral slurry.

[0038] In some embodiments, the CaF2 grade obtained by the fluorite flotation method is above 88.36%, and the CaF2 recovery rate is above 90.23%.

[0039] The fifth objective of this invention is to provide a calcite inhibitor for fluorite flotation, wherein the inhibitor comprises the birch bark crude extract described in any of the above technical solutions.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] The birch bark crude extract provided by this invention contains betulinol and betulinic acid. Their molecular formulas contain functional groups such as hydroxyl, carboxyl, and carbon six-membered ring. These functional groups are both hydrophilic and fixophilic groups, which have a strong adsorption effect on calcite. At the same time, the birch bark extract does not easily adsorb fluorite. This selective adsorption expands the flotation difference between gangue minerals calcite and fluorite, and can be used as a calcite inhibitor in the fluorite flotation process.

[0042] In particular, the extraction method provided by this invention is simple, efficient and low in processing cost. It can use a large amount of bark residue generated during the processing of birch trees as raw material. The birch bark extract obtained is inexpensive and more economical than high-purity birch triterpenoid products, thus having good application prospects.

[0043] Compared to commonly used inhibitors in existing technologies, such as water glass, birch bark crude extract has a better inhibitory effect, which can ensure better flotation effect with a smaller dosage, thus obtaining higher quality fluorite concentrate. Detailed Implementation

[0044] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be construed as limiting, but are merely intended to form the basis of the claims and to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0045] Example 1

[0046] This embodiment uses the following method to extract crude extract from birch bark:

[0047] Collect birch bark and dry it in the sun. Use a crusher to crush the birch bark to a thickness of less than -2mm.

[0048] Place birch bark in a round-bottom flask and add 95% ethanol solution to obtain a mixture in which the mass fraction of birch bark is 2%.

[0049] The mixture was stirred and soaked at room temperature for 120 hours at a stirring speed of 800 r / min, then filtered and the filtrate was collected.

[0050] The ethanol in the filtrate was recovered using a rotary evaporator, and a concentrated solution of the crude extract was obtained.

[0051] The concentrated solution of the crude extract was evaporated to dryness at 45℃ to obtain the crude extract of birch bark.

[0052] The crude extract of birch bark was dissolved in methanol to obtain an inhibitor solution with a mass fraction of 2% for later use.

[0053] The fluorite ore used in this embodiment is calcite-type fluorite ore, and its composition and the mass percentage of each component are as follows: CaF2 30.15%, CaCO3 6.1%, SiO2 50.3%. The specific operating steps are as follows:

[0054] First, take 250g of fluorite ore, grind it to a -74μm content of 70%, add it to a 0.5L flotation cell, and adjust the pH of the pulp to 8.5 with sodium hydroxide;

[0055] Add the above inhibitor solution at a dosage of 600 g / t of birch bark crude extract, stir for 4 minutes, then add 1000 g / t of sodium oleate to begin roughing. After roughing, rough concentrate and rough tailings are obtained. Add 500 g / t of sodium oleate to the rough concentrate for the first cleaning, resulting in a first-clean concentrate and first-clean tailings. Add 200 g / t of sodium oleate to the first-clean concentrate for the second cleaning, resulting in the final concentrate and second-clean tailings. Return the second-clean tailings to the previous cleaning operation. Perform a scavenging operation on the rough tailings without adding reagents. The flotation results are shown in Table 1.

[0056] Example 2

[0057] The inhibitor of birch bark crude extract was obtained using the same method as in Example 1.

[0058] The fluorite ore used in this embodiment is calcite-type fluorite ore, and its composition and the mass percentage of each component are as follows: CaF2 21.03%, CaCO3 8.21%, SiO2 50.12%. The specific operating steps are as follows:

[0059] Take 300g of fluorite ore, grind it to a -74μm content of 80%, add it to a 0.75L flotation cell, and adjust the pH of the pulp to 9.

[0060] Add the inhibitor solution of preparation number 500g / t to the crude extract of birch bark, stir for 5 minutes, then add 1200g / t of sodium oleate to start roughing. After roughing, a rough concentrate and a rough tailings are obtained. The rough concentrate is then treated with 600g / t of sodium oleate for the first cleaning, resulting in a first-clean concentrate and a first-clean tailings. The first-clean concentrate is then treated with 100g / t of sodium oleate for the second cleaning, resulting in the final concentrate and a second-clean tailings. The second-clean tailings are returned to the previous cleaning operation. The rough tailings are then subjected to a scavenging operation without the addition of reagents. The flotation results are shown in Table 1.

[0061] Example 3

[0062] This embodiment uses the following method to extract crude extract from birch bark:

[0063] Collect birch bark and dry it in the sun. Use a crusher to crush the birch bark to a thickness of less than -2mm.

[0064] Place birch bark in a round-bottom flask and add 85% ethanol solution to obtain a mixture in which the mass fraction of birch bark is 5%.

[0065] The mixture was stirred and soaked at room temperature for 180 hours at a stirring speed of 1000 r / min, then filtered and the filtrate was collected.

[0066] The ethanol in the filtrate was recovered using a rotary evaporator, and a concentrated solution of the crude extract was obtained.

[0067] The concentrated solution of the crude extract was evaporated to dryness at 45℃ to obtain the crude extract of birch bark.

[0068] The crude extract of birch bark was dissolved in methanol to obtain an inhibitor solution with a mass fraction of 2.5% for later use.

[0069] The fluorite ore used in this embodiment is calcite-type fluorite ore, and its composition and the mass percentage of each component are as follows: CaF2 17.25%, CaCO3 11.33%, SiO2 51.01%. The specific operating steps are as follows:

[0070] First, take 1000g of fluorite ore, grind it to -74μm content of 85%, add it to a 3L flotation cell, and adjust the pH of the pulp to 8.5 with sodium hydroxide;

[0071] The prepared inhibitor solution was added to the slurry at a dosage of 800 g / t of birch bark crude extract. After stirring for 5 minutes, 1500 g / t of sodium oleate was added to begin roughing. Roughing yielded rough concentrate and rough tailings. The rough concentrate was then treated with 450 g / t of sodium oleate for the first cleaning, yielding a first-clean concentrate and a first-clean tailings. The first-clean concentrate was then treated with 250 g / t of sodium oleate for the second cleaning, yielding the final concentrate and a second-clean tailings. The second-clean tailings were returned to the previous cleaning operation. The rough tailings were then subjected to a scavenging operation without the addition of reagents. The flotation results are shown in Table 1.

[0072] Example 4

[0073] The inhibitor of birch bark crude extract was obtained using the same method as in Example 3.

[0074] The fluorite ore used in this embodiment is calcite-type fluorite ore, and its composition and the mass percentage of each component are as follows: CaF2 18.5%, CaCO3 9.1%, SiO2 50.21%. The specific operating steps are as follows:

[0075] First, take 500g of fluorite ore, grind it to -74μm content of 80%, add it to a 1.5L flotation cell, and adjust the pH of the pulp to 8.5 with sodium hydroxide;

[0076] Add inhibitor solution to the slurry at a dosage of 750 g / t of birch bark crude extract. After stirring for 5 minutes, add 1200 g / t of sodium oleate to begin roughing. Roughing yields rough concentrate and rough tailings. Add 600 g / t of sodium oleate to the rough concentrate for the first cleaning, yielding primary cleaning concentrate and primary cleaning tailings. Add 150 g / t of sodium oleate to the primary cleaning concentrate for the second cleaning, yielding final concentrate and secondary cleaning tailings. Return the secondary cleaning tailings to the previous cleaning operation. Perform a scavenging operation on the rough tailings without adding reagents. The flotation results are shown in Table 1.

[0077] Example 5

[0078] This embodiment uses the following method to extract crude extract from birch bark:

[0079] Collect birch bark and dry it in the sun. Use a crusher to crush the birch bark to a thickness of less than -2mm.

[0080] Birch bark was placed in a round-bottom flask and 90% ethanol solution was added to it to obtain a mixture in which the mass fraction of birch bark was 2.5%.

[0081] The mixture was stirred and soaked at room temperature for 160 hours at a stirring speed of 1000 r / min, then filtered and the filtrate was collected.

[0082] The ethanol in the filtrate was recovered using a rotary evaporator, and a concentrated solution of the crude extract was obtained.

[0083] The concentrated solution of the crude extract was evaporated to dryness at 45℃ to obtain the crude extract of birch bark.

[0084] The crude extract of birch bark was dissolved in methanol to obtain an inhibitor solution with a mass fraction of 3% for later use.

[0085] The fluorite ore used in this embodiment is calcite-type fluorite ore, and its composition and the mass percentage of each component are as follows: CaF2 18.59%, CaCO3 12.31%, and SiO2 49.12%. The specific operating steps are as follows:

[0086] First, take 1000g of fluorite ore, grind it to -74μm content of 75%, add it to a 3L flotation cell, and adjust the pH of the pulp to 9 with sodium hydroxide;

[0087] Add inhibitor solution to the slurry at a dosage of 1000 g / t of birch bark crude extract. After stirring for 5 minutes, add 1400 g / t of sodium oleate to begin roughing. Roughing yields rough concentrate and rough tailings. Add 500 g / t of sodium oleate to the rough concentrate for the first cleaning, yielding primary cleaning concentrate and primary cleaning tailings. Add 250 g / t of sodium oleate to the primary cleaning concentrate for the second cleaning, yielding final concentrate and secondary cleaning tailings. Return the secondary cleaning tailings to the previous cleaning operation. Perform a scavenging operation on the rough tailings without adding reagents. The flotation results are shown in Table 1.

[0088] Example 6

[0089] The dosage of birch bark crude extract was 1800 g / t, the pulp pH was 7, the fluorite ore was ground to -74 μm with a content of 60%, and other conditions were the same as in Example 1. The flotation results are shown in Table 1.

[0090] Comparative Example 1

[0091] The only difference between Comparative Example 1 and Example 1 is that the 600 g / t birch bark crude extract in Example 1 was replaced with 1200 g / t water glass. The rest of the process was the same as in Example 1. The flotation results are shown in Table 1.

[0092] Comparative Example 2

[0093] The only difference between Comparative Example 2 and Example 2 is that the 500 g / t birch bark crude extract in Example 2 was replaced with 1500 g / t water glass. The rest of the process was the same as in Example 2. The flotation results are shown in Table 1.

[0094] Comparative Example 3

[0095] The only difference between Comparative Example 3 and Example 3 is that 800 g / t birch bark crude extract was replaced with 2000 g / t water glass. The rest of the process was the same as in Example 3. The flotation results are shown in Table 1.

[0096] Comparative Example 4

[0097] The only difference between Comparative Example 4 and Example 4 is that the 750 g / t birch bark crude extract in Example 4 was replaced with 1800 g / t water glass. The rest of the process was the same as in Example 4. The flotation results are shown in Table 1.

[0098] Comparative Example 5

[0099] The only difference between Comparative Example 5 and Example 5 is that the 1000 g / t birch bark crude extract in Example 5 was replaced with 2400 g / t water glass. The rest of the process was the same as in Example 5. The flotation results are shown in Table 1.

[0100] Comparative Example 6

[0101] The only difference from Example 6 is that the coarse extract of birch bark is replaced with water glass, with the same amount used. The flotation effect is shown in Table 1.

[0102] Table 1. Inhibitors and their dosages, and flotation effects in the examples and comparative examples.

[0103]

[0104]

[0105] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0106] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0107] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. The application of a crude birch bark extract as a calcite inhibitor, wherein the crude birch bark extract is obtained by the following extraction method: soaking birch bark in an extractant containing alcohol to obtain an extract solution, and then evaporating the solvent of the extract solution to dryness to obtain the crude birch bark extract.

2. The application according to claim 1, characterized in that, The application includes: in the flotation process of fluorite ore, using the crude extract of birch bark to selectively adsorb calcite, thereby separating calcite from fluorite ore.

3. The application according to claim 2, characterized in that, include: Fluorite ore containing calcite is prepared into a slurry, and then at least an inhibitor and a collector are added to the slurry for flotation, wherein the inhibitor includes crude birch bark extract.

4. The application according to claim 3, characterized in that, Specifically, it includes: The fluorite ore containing calcite is ground and slurry is prepared sequentially to obtain a slurry; the pH of the slurry is adjusted to 7-9; the inhibitor and collector are added sequentially to the slurry at the pH value for flotation.

5. The application according to claim 4, characterized in that: In the flotation process, the amount of crude birch bark extract used is 500-1800 g / t.

6. The application according to claim 4, characterized in that: In the flotation process, the amount of collector used is 800-1500 g / t.

7. The application according to claim 4, characterized in that: The collector includes one or more of sodium oleate, lauric acid, and oxidized paraffin soap.

8. The application according to claim 4, characterized in that, Also includes: The fluorite rough obtained from flotation is subjected to one or more fine cleaning processes, with a collector added in each fine cleaning process to obtain fluorite concentrate.

9. The application according to claim 8, characterized in that: In each selection process, the amount of collector used is 300-800g / t.

10. The application according to claim 4, characterized in that, Also includes: The tailings obtained from flotation are subjected to one or more scavenging processes to obtain the final tailings.

11. The application according to claim 4, characterized in that: In the slurry, minerals with a fineness of less than 74 micrometers account for 60%-85%.

12. The application according to claim 4, characterized in that: The concentration of solid minerals in the slurry is 40%-50%.

13. The application according to claim 4, characterized in that: After adding the inhibitor to the slurry, stir for more than 3 minutes, and then add the collector.

14. The application according to claim 4, characterized in that: The crude extract of birch bark was dissolved in methanol to prepare an inhibitor solution with a mass fraction of 0.5%, which was then added to the slurry.

15. The application according to any one of claims 1-14, characterized in that, The extraction method of the crude birch bark extract specifically includes: crushing the dried birch bark, soaking the crushed birch bark in an ethanol solution, filtering after soaking, and obtaining the extract solution.

16. The application according to claim 15, characterized in that: The dried birch bark is broken into pieces less than 2 mm before being soaked.

17. The application according to claim 15, characterized in that: Soak the birch bark in a 65%-95% ethanol solution, wherein the amount of ethanol solution added is such that the mass fraction of the birch bark is 2%-5%.

18. The application according to claim 15, characterized in that: The soaking time is more than 120 hours, and the stirring is carried out at a speed of 800-1200 r / min during the soaking process.

19. The application according to claim 15, characterized in that: The solvent in the extract solution is evaporated to dryness at a temperature of 40-65°C.

20. A flotation method for fluorite ore, characterized in that, include: Calcite-type fluorite ore is crushed to prepare a slurry, and then at least an inhibitor and a collector are added to the slurry for flotation; wherein the inhibitor includes a crude extract of birch bark obtained by the extraction method described in claim 1.

21. A calcite depressant for fluorite ore flotation, characterized in that: The inhibitor comprises a crude extract of birch bark obtained by the extraction method described in claim 1.

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